Fluid monitoring unit

ABSTRACT

A volume of fluid emanating from a cavity is regulated through a parallel conduit, pressurized system.

United States Patent [191 Fitzgerald [451 Aug. 21, 1973 [22] Filed:

[ FLUID MONITORING UNIT [75] Inventor: William M. B. Fitzgerald,Toronto, Ontario, Canada [73] Assignee: Johnson, Mathey and Mallory,Ltd., Toronto, Canada Nov. 24, 1970 [21] Appl. No.: 92,515

Related U.S. Application Data [60] Division of Ser. No. 786,971, Dec.26, 1968, Pat. No. 3,634,934, which is a continuation-in-part of Ser.No. 507,173, Nov. 10, 1965, abandoned.

[52] U.S. Cl 60/54.6 R [51] Int. Cl FlSb 7/00 [58] Field of Search60/545 E, 54.6 E,

[56] References Cited UNITED STATES PATENTS 2,095,560 10/1937 Vickers60/54.5 E 1,578,824 3/1926 Herbst et a1 60/546 E FOREIGN PATENTS ORAPPLICATIONS 237,116 7 10/1960 Australia ISO/54.6 E

Primary Examiner-Martin P. Schwadron Assistant Examiner-A. M. ZupcicAttorney-Richards H. Childress, Robert F. Meyer and Henry W. Cummings [57] ABSTRACT A volume of fluid emanating from a cavity is regulatedthrough a parallel conduit, pressurized system.

1 Claim, 1 Drawing Figure FLUID MONITORING UNIT This is a division ofapplication Ser. No. 786,971, filed Dec. 26, 1968, now U.S. Pat. No.3,634,934 which was a continuation-in-part of application Ser. No.507,173 filed Nov. 10, 1965, now abandoned.

This invention relates to an improved method of welding a metal facingto a base metal to form a composite headed contact, and to a machine forcarrying out such method. The method of the present invention isparticularly applicable to making rivet type composites having the shankand part of the head thereof fabricated from one metal and the facethereof having a layer of another metal or an alloy of the metal. It isalso believed that the present invention would be applicable totri-metal composites wherein a layer of one metal is sandwiched betweenother metals or alloys of metals.

In the manufacture of electrical contacts, use is being frequently madeof composite contacts wherein the contacts are manufactured of a lowcost base metal and a relatively higher cost material for the electricalcontact material. For example, composite rivet type electrical contactsare manufactured wherein the shank of the rivet and part of the head aremanufactured from a good thermally and electrically conductive materialsuch as copper, aluminum, and magnesium with the face of the head beingfabricated from a material which is also electrically and thermallyconductive and is also resistant to oxidation such as silver orsilver-cadmium oxide.

Because of the rising prices of materials such as silver, such compositecontacts are being more abundantly used. Consequently, industry isconstantly seeking means and methods for making such contacts. Among theproblems associated with the making of such contacts is that ofachieving a good uniform contact face on the head with a good bondbetween the contact face and the base metal. Such problems becomeparticularly acute with regard to the use of silvercadmium oxide as thecontact face material. Silvercadmium oxide becomes increasinglydifficult to bond to the base metal, such as copper, as the amount ofcadmium oxide increases.

Furthermore, in order to take advantage of the lower costmaterials, thecomposite contacts must, of necessity, be made at high production rateswith good quality and with close tolerances.

The present invention is concerned with the fabrica tion of compositearticles of manufacture, more particularly, composite rivet typecontacts, and has as one of its objects'the provision of a method ofproducing such articles.

Another object is the provision of a method of welding such articleswherein a facing is formed as part of the head of a rivet type articlewith the facing being joined to a base metal and then subsequentlyheaded to form the final article Still another object of the inventionis the provision of such a method wherein a uniform layer of such facingis achieved.

Yet another object of the invention is the provision of such a methodwherein the layer being joined to the base metal is formed with agreater thickness at the periphery prior to the heading step.

Still another object of the invention is the provision of such a methodwherein the base metal and the facing metal is heated prior to joining.

A further object of the invention is the provision of such a methodwherein the temperature of the base metal and the facing metal isregulated to achieve a desired facing configuration.

Still another object of the invention is to provide such a methodwherein the welding is achieved through rapid impact of pressure.

Another object of the invention is to provide such a method wherein theends of wire of predetermined length are welded together.

A further object of the invention is to provide such a method whereinthere is substantially no flow of the metals at the joint when the wiresare joined.

Another object of the invention is the provision of such a method whichis carried out in a vacuum.

Yet another object of the invention is the provision of a machine formaking the article.

A further object of the invention is the provision of a machine formaking the article at a high production rate.

Another object of the invention is to provide such a machine which ishydraulically operated in accordance with a programmed sequence.

Still another object of the invention is the provision of such a machinewherein there are means to heat, cut and feed wire stock to a centrallylocated work station.

Another object of the invention is to provide such a machine wherein thework station includes axial positioning means and support means.

Another object of the invention is to provide such a machine whereinhydraulic fluid is fed to various elements of the machine through anactuator means energized by a hydraulic programmer coupled to theactuator.

Another object of the invention is to provide an actuator meansincluding a chamber of fluid under pressure, passages communicating withan element of the machine to be actuated, and means controlling thefluid to the passages.

Another object of the invention is to provide a hydraulic programmerincluding a chamber of fluid under pressure, outlet means communicatingwith the chamber, and programming means selectively opening and closingthe outlet means. 7

Yet another object of the invention is to provide such a machine whereinan impact means is rapidly moved moved through a lever system to forcepredetermined lengths of wire into a support means and to join the wiresby impact in a single continuous stroke.

Still another object of the invention is the provision of a wire feedmeans utilizing a piston arrangement for selectively feeding wire.

Another object of the invention is the provision of a ram meansutilizing a travel multiplier means.

Another object of the invention is to provide a hydraulic valve means tocontrol the volume of fluid to an element being actuated.

Another object of the invention is to provide a hydraulic valve means tocontrol the pressure of a fluid to an element being actuated.

These and other objects and the nature thereof will become apparent fromthe following description taken in conjunction with the accompanyingdrawing wherein the sole FIGURE is a cross section of a valve means.

While the invention will be described with reference to the manufactureof electrical contacts, it should be understood that the invention neednot be so limited and that the purpose of the invention is to producecomposite articles havinga head and a shank wherein the head is composedof different materials.

According to the present invention, the metals comprising the electricalcontact are cut from continuous lengths of wire and then immediatelytransferred to a centrally disposed work station where the metals arejoined by pressing them together quickly at high pressure. The processis completed at the same work station by forming the welded metals underpressure into a rivet or composite disc. One or more of the metals maybe heated to assist in the joining process. All the operations may becarried out in a vacuum or in a protective atmosphere to ensureuncontaminated and oxide-free joints between the several metals of thecontact.

According to a further feature of the present invention, the operationsof uncoiling the wires, straightening the wires when necessary, shearingthe wires into accurate lengths, heating one or more of the lengths ofwire, joining several of the lengths of wire and forming the resultingcomposite rod to the required final shape are performed simultaneouslyand successively according to a repeating sequence in the same machine.

According to still further features of the present invention, theoperation of welding, indenting the shank when required and forming thecomposite rod into the required final shape are all performed while therod is in or partly in the confines of the work station. For thispurpose the work station is mounted in a central position on ahorizontal slab of metal and various tools are placed radially aroundthe die. Means are provided to advance each tool to a position over thedie. The tool performs its required function on the composite rod andthen is withdrawn to make way for the next operation. Suitable means areprovided to cool the die and the various tools surrounding it. Power forperforming the function of each tool is provided by an overhead rammeans mounted on the same axis as the work station. The ram means ispropelled downwards along the axis of the station at high velocity tosuccessively actuate the tools which perform the operations of weldingand forming the contact.

In carrying out the process of the invention, wires of a predeterminedlength of electrically and thermally conductive and oxidation resistantmaterial taken from the group consisting of silver, silver-cadmiumoxide, gold, platinum, paladium, and alloys thereof, is molecularlybonded to a wire of a predetermined length of an electrically andthermally conductive metal taken from the group consisting of copper,aluminum, magnesium, steel and alloys thereof to form a composite rodand the the composite rod is headed to form a rivet type article. Thematerials are molecularly bonded together very rapidly such that thematerial's grain structure is undamaged. A uniform layer of theelectrically and thermally conductive and oxidation resistant materialmay be assisted by forming a cup-shaped end portion on the material asthe composite is formed. Further, the temperature of both materials maybe kept below the eutectic, with the temperatures of the wires beingvaried to control the contour of the layer.

As will become apparent as the description proceeds, the joining of thewires takes place at a centrally located work station having a supportmeans, or a die, the diameter of which is only slightly larger than thediameter of the wires. The head is then fonned outside the die. Thusthere is substantially no displacement of the metals at the joint, and amore uniform contact layer is achieved. Also, as will become apparent,high mass production rates with good quality contacts are achieved byperforming all of the operations at a central work station with thematerials being forced into the station and joined by a singleapplication of pressure, such pressure being rapidly applied as animpact stroke. Prior art means and methods, whereby different functionsare performed at different stations with the machine indexing fromstation to station, are for the most part slower and in addition,alignment of the materials was difficult to achieve thus causingproduction problems.

Referring now to the drawing, there is shown valve means 237 of FIG. 15of the above-noted parent application Ser. No. 786,971 which givesaccurate control of the volume of the hydraulic fluid being sent to theelement of the machine which it is energizing. In the present machine,such element is the ram means 232 described in the above-noted parentapplication where such volume control is required. Valve means 237includes a housing 239 having disposed therein a cavity 241 for piston242, fluid conduits 243, 244 and 245, piston means 246 having extendedtherefrom valve stem 247 which is biased against valve seat 248. Apiston means 242 is connected to piston 242 and is biased by beingexposed to atmospheric pressure. Conduit 244 is in parallel with cavity241 and serves as a by-pass for the fluid when the fluid is returning orwhen the limiting effect of piston 242 is no longer required. The travelof piston 242 is determined by stop means 249, the position of which isset by set screw 251 with the set position being maintained by set screw252.

As previously noted, the present valve is used to accurately control thevolume of the fluid disposed. Such control is achieved by the use of theparallel circuit of the conduit 244 and cavity 241. With the valve inthe position shown, there is fluid in conduit 243, conduit 244 and incavity 241 above the piston 242. Valve stem 247 will be seated in valveseat 248 by fluid pressure being applied against piston 246 throughinlet means 253. Such fluid could, for example, be fed from anotherelement of the machine in accordance with a programmed sequence. Forexample, in the present use of the valve where the valve is being usedto control the volume of fluid to the ram means, the fluid coming toinlet 253 could be taken from the cutter means 222 of FIG. 21 of theabove-noted parent application. There will also be fluid in conduit 245,the fluid being fed to inlet means 254 from actuator means 202 of FIG.20. When actuator means 202 of FIG. 20 is actuated fluid flows to piston242 moving the piston against stop means 249 to force fluid from conduit243 to the ram means through outlet 255. When the volume of fluidthrough the ram means is no longer required, the pressure against piston246 is released. Prior to, simultaneously or after, actuator means 202of FIG. 20 of the above-noted application, releases the pressure toinlet 254 such that there will be less pressure in conduits 244 and 245.Residual fluid pressure of the system will be higher than atmospheric.The cross sectional area of the top of piston 242 less the crosssectional area of the bottom of piston 242 being equal to the crosssectional area of piston 242', and as the fluid pressure inside cavity241 and conduit 245 is greater than the pressure below piston 242, thepiston 242 will return to its "at rest" position and fluid will flowthrough conduit 244 and 245 such that the fluid system-falls to theresidual fluid pressure and thus be ready for the next stroke of theram. By using the parallel connection of the cavity 241 and conduit 244,the system can always be neutralized regardless of the positioning ofthe stop means 249.

I claim:

1. A fluid monitoring unit comprising a. a housing,

b. a cavity in said housing,

c. a first piston operable within said cavity,

d. means limiting the travel of said piston,

e. first and second fluid inlets,

f. first and second conduits disposed in spaced, substantially parallelrelationship connecting said inlets at opposed ends of said cavity,

.g. a third condiut communicating with said first and piston.

1. A fluid monitoring unit comprising a. a housing, b. a cavity in saidhousing, c. a first piston operable within said cavity, d. meanslimiting the travel of said piston, e. first and second fluid inlets, f.first and second conduits disposed in spaced, substantially parallelrelationship connecting said inlets at opposed ends of said cavity, g. athird condiut communicating with said first and second conduits, h. asecond cavity communicating with an intersection of one of said firstand second conduits and said third conduit, i. a second piston disposedwithin said second cavity and operable to engage a valve stem to closesaid third conduit at said intersection, and j. fluid inlet meanscommunicating with said second piston.